User Plane Function
Source:: What is the 5G User Plane Function (UPF)? (metaswitch.com)
The UPF represents the data plane evolution of a Control and User Plane Separation (CUPS) strategy, which is a fundamental component of the 3GPP 5G Core Network.
It plays the most critical role in the process of data transfer. It provides the interconnect point between the mobile infrastructure and the Data Network (DN), i.e. encapsulation and decapsulation of GPRS Tunneling Protocol for the user plane (GTP‑U).
It facilitates in user plane operations, such as packet routing and forwarding, interconnection to the Data Network, policy enforcement and data buffering.
The User Plane Function has four distinct reference points:
- N3: Interface between the RAN (gNB) and the (initial) UPF.
- N9: Interface between two UPF’s (i.e. the Intermediate I-UPF and the UPF Session Anchor)
- N6: Interface between the Data Network (DN) and the UPF
- N4: Interface between the Session Management Function (SMF) and the UPF
Its implementation by OpenAirInterface community can be found here: oai / cn5g / oai-cn5g-upf-vpp · GitLab (eurecom.fr)